Path: chuka.playstation.co.uk!macpaul
From: macpaul@ndirect.co.uk (Paul Harvey)
Newsgroups: scee.yaroze.beginners
Subject: Re: GpuPacketArea query.
Date: Tue, 15 Sep 1998 22:35:06 +0000
Organization: PlayStation Net Yaroze (SCEE)
Lines: 34
Message-ID: <1dff5c0.3h50mz1xfnn40N@th-pm05-19.ndirect.co.uk>
References: <35557807.6E248247@chowfam.demon.co.uk> <3558DF85.7C89DA42@ndirect.co.uk> <3559D87E.D5C1EBD1@chowfam.demon.co.uk> <3594C013.116@manc.u-net.com> <uu355qa8l.fsf@cybec.com.au> <01bda34b$a5fc6c20$f30b0a0a@Angela1.intelligent-group.com>
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Craig Graham <c_graham@hinge.mistral.co.uk> wrote:

> Toby Hutton <thutton@cybec.com.au> wrote in article
> <uu355qa8l.fsf@cybec.com.au>...
> > James Shaughnessy <james@manc.u-net.com> writes:
> > 
> > > PS I still use the old formula for packet space:
> > > PACKET GpuPacketArea[2][NUM_SPRITES*sizeof(GsSPRITE)];
> > > "sizeof(GsSPRITE)" is a macro unless I'm very much mistaken.
> > 
> > sizeof is actually a C operator, and GsSPRITE is a struct.  You can
> > use sizeof with any variable or data type to return its size.
> > 
> > If you're doing 2D only with sprites then NUM_SPRITES * sizeof
> > (GsSPRITE) would work fine.  A packet can be other things though, like
> > a poly or line which are different sizes, perhaps larger than
> > GsSPRITE, so you need to make sure you reserve plenty of space.
> 
> That's not quite true, as a GsSPRITE when entered using GsSortSprite()
> (as opposed to GsSortFastSprite) actually generates the same type of GPU
> packet as a texture mapped Quad (different front end to the same low-level
> primitive).
> 
> > Toby.
> 
> Craig.


Where on earth does a yaroze member pick up such technical details as
this?!!!! The Packet area is nothing short of a great mystery. It's
interesting to hear some tech on packet sizes, etc, but how do you come
by this, or do you just need to be _really_ clever?!

~md